Method for hydrodynamically subjecting a goods line, optionally with finite preproducts, to water jets and nozzle device for producing liquid jets

ABSTRACT

Water needling is used to constantly subject the entire surface of a width of a goods line to water jets. However, it is also advantageous for units of commodity goods that are to be consolidated and optionally, if a cover nonwoven supporting these goods only needs to be consolidated around them or if a cover nonwoven is to be bonded around the goods. All possible patterns, such as line or strip consolidation, are advantageous. This is made possible by the invention, which provides for measures which specifically control, e.g. partially impede and/or interrupt the flow of the water jets from a water beam. This can occur by means of cover panels which advance with the line, supported by a screen or by means of a screen alone. Individually movable, computer-controlled nozzles are also advantageous for partial consolidation.

WO 00/63479 teaches the supporting of even three-dimensional finitematerials, such as starting products or intermediate products, betweentwo fabric webs such as nonwovens, employing hydrodynamic needling toconnect and consolidate the nonwovens by felting their fibers, and thussealing the materials three-dimensionally.

Insofar as the consolidation process proceeds continuously along thelength of the advancing sandwich web—regardless of whether thethree-dimensional materials run parallel or perpendicular to the fabricweb's direction of transport—this approach is no different than thepreviously known consolidation method by needling according to, forexample, U.S. Pat. No. 3,508,308. If the materials are finite, however,and if the goal is not to treat them, or to treat them only partially,with water jets in the region of the materials, then the materials arenot able to be partially consolidated two-dimensionally, or wrappedthree-dimensionally, using the previously known methods.

The goal of the invention is to find a method, and associated device, bywhich even such finite materials as prefabricated padding and/orabsorbent inserts for diapers, surgical pads, compresses, possibly alsopatches or similar finished products, may be consolidated continuously,possibly partially over their entire surface, but possibly also bondedto the, possibly two, advancing upper and lower nonwovens or the like,partially three-dimensionally, while excluding the surface of thematerials—with the result that the materials are three-dimensionallyenclosed and sealed. The final products for sanitary, medical, or otherapplications should be capable of being treated continuously, buttargeted to the specific, even three-dimensional product, in varyingways over their surface.

Situations are also conceivable whereby a two-dimensional nonwoven ornonwoven product is compacted, and also consolidated, over its surfaceonly partially, or in order to achieve certain effects on its surface.The method to be found should thus also be useful for modifying the formof this only partial consolidation of the nonwoven or compound material.

Based on a method of hydrodynamic compaction and/or consolidation and/orbinding in the case of at least two superimposed nonwovens, tissues, orwoven or knitted materials using fluid jets acting uniformly over theworking surface, whereby a fluid is sprayed from the jet strip of a jetmanifold, the strip extending over the working width, from fine jetorifices arranged closely in rows at a high pressure of up to 1000 baragainst a fabric web advancing opposite the jet manifold, the inventionachieves the goal by briefly preventing the fluid jets emergingcontinuously, unmodified, from the jet manifold from striking theadvancing fabric web so as to leave sections, lines, or surfaces of thefabric web untreated by the water jets. The water jets or the waterpressure may also be generated in unmodified fashion within the watermanifold, after which the water jets are at least partially preventedfrom reaching the fabric web. This is possible, for example, by brieflydiverting the water jets from their generated direction by moving anobject into the flow direction of the water jets in a time-definedmanner, the object consequently modifying the trajectory of the waterjets, possibly for a brief moment. This technique allows products toremain untreated in regions where the purpose is to allow them to retainloft, thus preserving the specific absorption capacity of the existingproducts.

A similar effect may be achieved by having the individual jet orifices,groups of jet orifices, or individual segments of a wider jet manifoldbe supplied intermittently with fluid, or discharge the fluidintermittently—an effect which may be achieved by electromechanically,electromagnetically, or piezoelectrically controlled valves or groups ofvalves (in parallel or sequentially). Such techniques enable pulsatingfluid jets to be directed in situ, that is, against specific, preciselydefined regions of the material to be treated hydrodynamically, therebyachieving strengthening or consolidation according to a predefinedpattern.

This is similarly possible if the object moving into the trajectory ofwater jets is part of a belt moving along with the fabric web, or partof the peripheral surface of a drum. One aspect that must be consideredhere, however, is that the required surface on the belt or drum is ableto be guided or held laterally, and thus advanced. Consequently, thisfluid-permeable region, such as a screen or perforated panel mustpresent at least partial resistance along the jets of fluid. The resultis any desired pattern such as a weave or waffle pattern in theconsolidation zone. Multiple application examples exist. Paper may beprovided with a kind of watermark, or tissue may be provided with asurface structure customized for the production company or itscustomers. Typical examples here include absorbent cotton products whichare provided on one or both sides with a light surface structure whichhas a linear depression, that is, a network, of parallel straight oralternate lines.

Another approach to achieving the goal is to have the jet manifold orthe jet orifices move relative to the fabric web, or vice versa. At thesame time, it is also possible to affect the discharge of water from thejet or the jet manifold in terms of pressure and/or volume at shortintervals. A variety of methods are conceivable to implement this idea.Individual jet orifices may be used which are connected to the pressurepump creating the water pressure. However, a conventional jet manifoldmay also be employed to which individual jet orifices are connected, thejet orifices being in turn provided with valves which use a computer,for example, to create or not to create a specific pattern using waterjets. This approach may also be employed to reduce in a targeted fashionthe treatment of the consolidation material, or to concentrate it onspecific partial surfaces, points, or lines. To do this, an intermittentaction or pulsation of the jets is required.

This punctiform or short broken-line-type needling may be used toachieve a kind of hydrodynamic sewing, basting, or tacking, i.e. toachieve this without any thermoplastic consolidation of the nonwovenproduct which would diminish the desired absorption effect of theproduct. The flexibility provided in this area is enormous.Consolidation may be effected for all formats or patterns. The systemmay be applied specifically to the medical industry.

Using this approach, previously individually fabricated startingproducts may be given final treatment, consolidated, and enclosed inenvelopes continuously. After drying and/or additional enhancement, theproduct web may be wound up in large rolls, as is usual with thesediscontinuous products, shipped out, or, after transverse andlongitudinal separation, sent on locally for individual applications orfor packaging in boxes, etc.

The drawing presents in schematic form several examples of devices forimplementing the method according to the invention.

FIG. 1 is a top view of a fabric web having plastically raised productsspaced at intervals next to each other;

FIG. 2 is a side view of a water manifold, insertion plate, and fabricweb;

FIG. 3 is a side view similar to that of FIG. 2 including a means ofpunctiform consolidation;

FIG. 4 shows controllable individual jet orifices with details a)through d);

FIG. 5 is a cross-section of a jet manifold within a continuous beltadvancing with the fabric web, the network structure of which belt issealed by impermeable regions visible in FIG. 6.

A jet manifold is composed essentially of components such as thosedescribed in European Patent A-0 725 176. The disclosure of thisOffenlegungsschrift is therefore incorporated herein by reference.

A jet manifold 1, such as that shown in simplified form in FIG. 4 a), iscomposed of a housing having at least one longitudinal hole 2, to thefront of which a fluid is supplied under pressure. The water movesthrough passages 3 to the jet strip 4 in which spaced jet orifices areincorporated, usually in two rows adjacent to each other. Water jets 5form within these orifices, the jets beating against the fabric web 6advancing below and consisting of at least one, for example, nonwovenundergoing fiber entanglement.

As seen in FIG. 1, fabric web 6 is composed of a lower carrier nonwoven6′ on which two-dimensional starting products 7 such as padding,absorbent inserts for diapers, patches, pads, or the like aresuperimposed. The requirement here is to punctiformally consolidate ortack the consumer goods 7 shown, and as a result, the punctiformconsolidation 8 is marked here at four locations. The remaining regionis to remain unmodified, retaining loft so as to remain highlyabsorbent. A two-dimensional cover nonwoven 6″ is then superimposed onthis consumer good 7. Special hydrodynamic needling is then used tocombine everything, as indicated by the hatched areas.

To accomplish this, FIGS. 2 and 3 provide a side view or cross-sectionalview showing water jets 5 from a jet manifold, not shown here, apossibly reciprocating object 9 which has in this example a profile cutinto the front edge 10; and provide a cross-sectional view of fabric web6 showing where the special non-consolidation or punctiformconsolidation is effected. As a result of the partially effective waterjets 5, consumer goods 7, or nonwovens 6′ and 6″ are struck only at thedesired locations. This effect is achieved by object 9, here identifiedas a plate. Plate 9 has a front edge 10 which is reciprocatingly movablerelative to fluid jets 5 emerging uniformly from the jet manifold overthe working width. The projecting profiles 10′ of plate 9 move underwater jets 5 such that these water jets striking plate 9 do not strikefabric web 6 moving below—thereby leaving the finished product with loftand thus highly absorbent at that location. FIG. 2 shows the projecting,profiled cover regions 10′ at the width of consumer goods 7 since theseare not struck here by water jets 5′ and thus retain loft, while thecover regions 10″ of plate 9′ in FIG. 3 are narrower, specifically, of anarrower form at the width of segments 7′ due to the punctiformconsolidation 8 so that water jets 5′ impact only at points 8 andconsolidate consumer goods 7 only at those locations.

To achieve a consolidation required in multiple steps, as shown in FIG.1, multiple plates 9, 9′ are provided in tandem with one water manifoldeach. Individual plates 9, 9′ are moved independently of each other inreciprocating motion at different frequencies.

It is also possible here to employ differently fabricated jet stripswhich are effective over their length with differently perforated and/ornon-perforated regions within the jet manifold. If, for example, jetstrips 4 have holes only where the water jets 5′ emerge in FIGS. 2 and3, then a simple reciprocating plate 9 with a straight front edge 10 issufficient to create a consolidation in the region of products 7intermittently or only at point locations.

Jet strips with holes distributed differentially over their length orwith non-perforated regions may also function on their own to effectintermittent consolidation. In this way, patterns may be incorporated inthe nonwoven by jets which match the design of the jet strips.

Individual jet orifices or smaller water manifolds 1 are provided in theembodiment of FIG. 4. The individual jet orifices here have a circularjet plate 4′, as in FIG. 4 b, or a strip-like jet plate 4″ with only afew holes for water jets 5, as in FIG. 4 c. The individual jet orificesof FIG. 4 d may move along a path controlled by a computer, therebyconsolidating any desired pattern to be marked on fabric web 6. Theindividual jet orifices allow better control in terms of the suppliedvolume and pressure of the fluid. These jet orifices enable nonwoven 6possibly to be perforated or tacked in a line pattern—for example, toallow easier separation of the border sections or of consumer goods 7from each other. The individual jet orifices may also be arranged atdifferent levels along the border regions of the fabric web, or orientedat specially adjusted inclinations. The individual jet orifices 1 ofFIG. 4 d must be supplied with the required pressurized water. Theindividual jet orifices are either connected by movable hoses 18 to thepressure pump, or these hoses 18 are connected to a water manifold ofconventional design. Water manifold 1 is then located along the width ofthe fabric web, to which manifold a series of hoses 18 are attached in apressure-tight manner, extending up to individual jet orifices 1. Thejet orifices may be equipped with valves which modify the water pressureof the water manifold depending on the pressure or volume of fluidrequired at the specific location of fabric web 6. All of this may becontrolled by a computer.

Consumer good 7 may be consolidated with the same pattern, also usingthe device of FIG. 5. Here a continuous belt 15 moves along with fabricweb 6 and completely covers the surface of fabric web 6 with a screen.In place of a continuous belt, a drum having a large free surface mayalso be advantageous. Water manifold 1 is located on the inner side ofcontinuous belt 15, the manifold spraying fluid jets uniformly againstthe belt over its entire length. However, belt 15 has regions 16 whichare impermeable to fluid. The cover regions 16 match the pattern to beneedled, for example corresponding to the consumer goods 7 found in FIG.1, with openings 17 for punctiform needling. In this way, othertwo-dimensional patterns may also be needled, embossed, in and on fabricweb 6, depending on the continuous belt 15 providing a pattern. Thistype of consolidation, however, affects a pattern even on theconsolidated regions of the nonwoven, which pattern corresponds to thetype and pattern texture, of continuous belt 15.

1. Method of hydrodynamic compaction and/or consolidation and/or bindingin the case of at least two superimposed nonwovens, tissues, or woven orknitted materials using fluid jets acting uniformly over the workingsurface, whereby a fluid is sprayed from the jet strip of a jetmanifold, the strip extending over the working width, from fine jetorifices arranged closely in rows at a high pressure of up to 1000 baragainst a fabric web advancing opposite the jet manifold, characterizedin that the fluid jets emerging continuously, unmodified, from the jetmanifold are briefly prevented from striking the advancing fabric web soas to leave sections, lines, or surfaces of the fabric web untreated bythe water jets.
 2. Method of hydrodynamic compaction and/orconsolidation and/or binding in the case of at least two superimposednonwovens, tissues, or woven or knitted materials using fluid jetsacting uniformly over the working surface, whereby a fluid is sprayedfrom the jet strip of a jet manifold, the strip extending over theworking width, from fine jet orifices arranged closely in rows at a highpressure of up to 1000 bar against a fabric web advancing opposite thejet manifold, characterized in that the fluid pressure actingcontinuously, unmodified within the water manifold, is intermittentlyprevented from generating water jets so as not to strike the advancingfabric web in this region in order to leave sections, lines, or surfacesof the fabric web untreated by the water jets.
 3. Method according toclaims 1 or 2, characterized in that the water jets are briefly divertedfrom their direction of generation.
 4. Method according to claims 1, 2or 3, characterized in that an object is moved into the flow directionof the water jets, which object changes the trajectory of the waterjets.
 5. Method according to one of the foregoing claims, characterizedin that the object is inserted into the trajectory of the water jets ina time-defined manner.
 6. Method of hydrodynamic compaction and/orconsolidation and/or binding in the case of at least two superimposednonwovens, tissues, or woven or knitted materials using fluid jetsacting uniformly over the working surface, whereby a fluid is sprayedfrom the jet strip of a jet manifold, the strip extending over theworking width, from fine jet orifices arranged closely in rows at a highpressure of up to 1000 bar against a fabric web advancing opposite thejet manifold, the fabric web being covered by a continuous screen ordrum advancing at the same rate of speed, characterized in that thefluid jets emerging continuously, unmodified, from the jet manifold arebriefly prevented from striking the advancing fabric web so as to leavesections, lines, or surfaces of the fabric web untreated by the waterjets.
 7. Method according to claim 5, characterized in that surfaceregions advance along with the continuous screen or peripheral surfaceof the drum, which regions prevent and/or reduce the passage of waterstriking the fabric web in a timed or rhythmic manner.
 8. Methodaccording to one of the foregoing claims, characterized in that thediverted fluid not striking the fabric web is immediately extracted bysuction above the fabric web.
 9. Method of hydrodynamic compactionand/or consolidation and/or binding in the case of at least twosuperimposed nonwovens, tissues, or woven or knitted materials usingfluid jets acting uniformly over the working surface, whereby a fluid issprayed from the jet strip of a jet manifold or jet orifice, the stripextending only partially over the working width, from fine jet orificesarranged closely in rows at a high pressure of up to 1000 bar against afabric web advancing opposite the jet manifold or jet orifice, and thejet manifold or jet orifices are controlled in terms of motion relativeto the fabric web, or vice versa, so as to leave sections, lines, orsurfaces of the fabric web untreated by the water jets.
 10. Methodaccording to one of the foregoing claims, characterized in that thedischarge of water from the jet orifice or jet manifold is controlled atshort intervals in terms of pressure and/or volume.
 11. Method accordingto claim 10, characterized in that, by employing a punctiform settingaction with this approach a nonwoven product is hydrodynamically tackedor “sewn.”
 12. Method according to claim 10 or 11, characterized in thatindividual jet orifices, groups of jet orifices, or segments of a widerjet manifold are supplied with fluid from a high-pressure line byindividual or multiple electromechanically, electromagnetically, orpiezoelectrically controlled valves or groups of valves.
 13. Devicehaving a jet manifold to implement the method according to one of theforegoing claims, as part of a device to generate fluid jets for the jettreatment of fibers of at least one web, such as a fiber web, tissue, orwoven or knitted material, the web being carried by a drum or continuousbelt along the manifold, which manifold is composed of an upper sectionand a lower section extending at least partially over the working widthof the web, wherein a pressure chamber of circular cross-section islocated in the upper section over the length of the manifold, to whichchamber the fluid is fed under pressure, for example, at the front end,and wherein a jet plate with openings for the jet orifices is mounted ina fluid-tight manner in the lower section, characterized in that the jetstrip (4) has over its length certain regions which are not providedwith jet orifices (5, 5′), thereby preventing passage of the water, orcreation of the water jets, along these regions.
 14. Device according toclaim 17, characterized in that the jet strip has certain regions overits length having a different number of jet orifices, or having orificeswith different diameters.
 15. Device having a jet manifold to implementthe method according to one of the foregoing claims, as part of a deviceto generate fluid jets for the jet treatment of fibers of at least oneweb, such as a fiber web, tissue, or woven or knitted material, the webbeing carried by a drum or continuous belt along the manifold, whichmanifold is composed of an upper section and a lower section extendingat least partially over the working width of the web, wherein a pressurechamber of circular cross-section is located in the upper section overthe length of the manifold, to which chamber the fluid is fed underpressure, for example, at the front end, and wherein a jet plate withopenings for the jet orifices is mounted in a fluid-tight manner, andwherein the fabric web is covered by a parallel-traveling continuousscreen impinged by the fluid jets or by a drum, characterized in thatthe continuous screen (15) or the peripheral surface of the drum hasfluid-impermeable regions (16) distributed over its working surface. 16.Device according to claim 15, characterized in that thefluid-impermeable regions (16) have orifices (17) for the passage offluid jets.
 17. Device having multiple jet manifolds or jet orifices ina housing to implement the method according to one of the foregoingclaims, as part of a device to generate fluid jets for the jet treatmentof fibers of at least one web, such as a fiber web, tissue, or woven orknitted material, the web being carried by a drum or continuous beltalong the manifold, which manifold is composed of an upper section and alower section extending at least partially over the working width of theweb, wherein a pressure chamber of circular cross-section is located inthe upper section, to which chamber the fluid is fed under pressure, andwherein a jet plate with openings for the jet orifices is mounted in afluid-tight manner, characterized in that the jet manifolds (1) or thejet orifices are not fixed within the housing but are movably supportedand electronically controlled.
 18. Device according to claim 17,characterized in that the jet manifolds or jet orifices are oriented indifferent directions such as perpendicular or oblique relative to theadvancing fabric web.
 19. Device according to claim 17, characterized inthat the jet manifolds or jet orifices are arranged at different levelsand/or are movable relative to the fabric web (6) or to thethree-dimensional products (7).
 20. Device according to claim 17,characterized in that the trajectories of the jet orifices arecontrollable by a computer.
 21. Device, specifically one according toclaims 17 through 20, characterized in that the fluid discharge from thejet orifices is controllable by one or more valves.
 22. Device accordingto claim 21, characterized in that the valves or valve groups areelectromechanically, electromagnetically, or piezoelectricallycontrolled.
 23. Device according to claims 17 through 22, characterizedin that the jet manifolds or jet orifices are connected to a pressurepump or a water manifold by pressure hoses (18).
 24. Device according toone of claims 17 through 23, having an suction extraction device belowthe fabric web, characterized in that the suction extraction device ismovable along with the jet orifice, or extends along the trajectory ofthe jet orifice.